i have made an "electronic" 8bit calculator (not "mechanical" calculator) with the Beta demo of "Little big planet" (a new PS3 game with an editor for create). it do decimal/binary conversions and it can do Add and Sub. There are probably more simple solutions for calculator machine but i was more interested by this "electronic" solution for the fun computation take clearly less that a half
![LittleBigPlanet : Little Big Computer](https://cdn-ak-scissors.b.st-hatena.com/image/square/b01e42c884d68cde10c36d2526da0ed03f832fde/height=288;version=1;width=512/https%3A%2F%2Fi.ytimg.com%2Fvi%2FZiRgYBHoAoU%2Fhqdefault.jpg)